Three tiny rocks brought from the moon by an unmanned craft will hit the market at a price tag up to one million U.S. dollars on Thursday at the Sotheby's in New York.

According to the auction house, the moon rocks will headline Sotheby's Space Exploration auction on November 29, offered with an estimate of 700,000 - 1,000,000 U.S. dollars. The sale will mark just the second time that an actual piece of another world has ever been offered for public sale.

These lunar samples, collected in 1970 via a Soviet space program, were given as a gift to the widow of the Sergei Pavlovich Korolev, the former director of the Soviet space program, who made great contributions to the space exploration.

Since the samples were first put up for the auction in 1993, they have been in the hands of an unnamed American individual until now.

"What's so exciting about these is they are the only documented lunar samples that can legally be owned by a private person," Cassandra Hatton, Sotheby's Vice President and Senior Specialist, said.

Previous fragments got from the moon usually remain with countries who collected them. "These samples are subject to laws governing public gifts, and in most cases, as in the United States, the law does not currently allow for public gifts to be transferred to an individual," said Sotheby.